US6627140B1 - Method for manufacturing diaphragm for loudspeaker - Google Patents

Method for manufacturing diaphragm for loudspeaker Download PDF

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Publication number
US6627140B1
US6627140B1 US09/485,037 US48503700A US6627140B1 US 6627140 B1 US6627140 B1 US 6627140B1 US 48503700 A US48503700 A US 48503700A US 6627140 B1 US6627140 B1 US 6627140B1
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United States
Prior art keywords
diaphragm
loudspeaker
manufacturing
speaker diaphragm
reactive chamber
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Expired - Fee Related
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US09/485,037
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English (en)
Inventor
Hitoshi Sato
Sinya Mizone
Kiyoshi Ikeda
Hiroko Yamazaki
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. reassignment MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: IKEDA, KIYOSHI, MIZONE, SINYA, SATO, HITOSHI, YAMAZAKI, HIROKO
Priority to US10/613,456 priority Critical patent/US20040094357A1/en
Priority to US10/613,455 priority patent/US7072485B2/en
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Publication of US6627140B1 publication Critical patent/US6627140B1/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H04R31/003—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor for diaphragms or their outer suspension

Definitions

  • the present invention relates to the field of methods for manufacturing speaker diaphragms employed in a range of audio equipment, speaker diaphragms made using such methods, and speakers employing such diaphragms.
  • a magnetic circuit 15 includes a magnet 15 a , lower plate 15 b , and upper plate 15 c.
  • a frame 16 is bonded to the magnetic circuit 15 .
  • a damper 17 holds a voice coil 18 .
  • the outer circumference of the damper 17 is bonded to the frame 16 , and its inner circumference is bonded to the voice coil 18 whose coil 18 a is embedded in the magnetic gap 15 d of the magnetic circuit 15 .
  • a speaker diaphragm 19 is bonded to the frame 16 via an edge 19 a bonded to its outer circumference, and the inner circumference of the speaker diaphragm 19 is bonded to the voice coil 18 .
  • This speaker diaphragm 19 is generally made mainly of paper or thin resin plates, which is selected depending on the need for weather resistance and required acoustic characteristics.
  • a speaker diaphragm made of polyethylene which is a type of polyolefin system, has low material density which gives the speaker diaphragm a low mass. It also has relatively large internal loss with respect to mechanical vibration, which improves the frequency characteristic of the speaker. Accordingly, polyethylene speaker diaphragms are commonly used in speakers. However, a polyethylene speaker diaphragm has low adhesivity, making it essential to activate the surface of the speaker diaphragm to improve bonding strength.
  • Common conventional methods for activating the surface of the speaker diaphragm 19 include the application of primer after corona discharge, and surface treatment of the speaker diaphragm 19 by the gas plasma treatment method using parallel flat electrodes 20 and 21 as shown in FIGS. 8 and 9.
  • the conventional surface activating technology for treating the surface of the speaker diaphragm has the following disadvantages.
  • a large processing apparatus is required because only the areas close to electrodes 20 and 21 are activated if the electrodes are small, causing a deviation in wettability of the speaker diaphragm 19 .
  • this treatment takes about 30 seconds for one face of the speaker diaphragm 19 .
  • the workpiece then needs to be flipped or the speaker diaphragm 19 needs to be flipped to apply treatment to the other face, requiring more than one minute for each piece and seriously degrading productivity.
  • the speaker diaphragm may deform during corona discharge due to high temperatures above 80° C. in the reactive chamber.
  • the method using the parallel flat electrode 20 in FIG. 8 also creates the risk of heat deformation and low productivity of the speaker diaphragm 19 .
  • the method using the parallel flat electrode 21 in FIG. 9 may also cause low productivity. If more than one speaker diaphragm 19 is handled at once to solve the problem of low productivity, it may still have the risk of heat deformation, and significant difference in wettability between the periphery and the center.
  • the present invention aims to solve these disadvantages.
  • the present invention offers a speaker diaphragm with stable quality and a speaker employing such diaphragm.
  • the method for manufacturing a speaker diaphragm of the present invention involves the next steps.
  • a resin speaker diaphragm made by injection molding or sheet forming by heating is disposed in a reactive chamber, and electrodes are provided outside of the reactive chamber.
  • Plasma is applied to the speaker diaphragm to activate the surface. Provision of electrodes outside the reactive chamber enables to keep the temperature of the reactive chamber below the heat deformation temperature of the speaker diaphragm during plasma treatment. Accordingly, heat deformation of the speaker diaphragm is preventable and defects caused by heat deformation can be suppressed.
  • FIG. 1 is a perspective view illustrating a method for manufacturing a speaker diaphragm in an exemplary embodiment of the present invention for describing plasma treatment of the speaker diaphragm.
  • FIG. 2 is a sectional view illustrating the speaker diaphragm aligned in a quartz reactive chamber, which is a key part of the exemplary embodiment of the present invention.
  • FIG. 3 is a temperature change graph during consecutive operation of the quartz reactive chamber in the exemplary embodiment of the present invention.
  • FIG. 4 is a comparison of durability of wettability in the exemplary embodiment of the present invention.
  • FIG. 5 is a sectional view illustrating the bonding state of the speaker diaphragm and a voice coil.
  • FIG. 6 is a sectional view illustrating the bonding state of the speaker diaphragm and an edge.
  • FIG. 7 is a side sectional view of a conventional speaker.
  • FIG. 8 is a sectional view of an essential portion of a conventional speaker illustrating plasma treatment for the speaker diaphragm using parallel flat electrodes.
  • FIG. 9 is a sectional view of an essential portion of a conventional speaker illustrating plasma treatment for the speaker diaphragm in FIG. 8 using another type of parallel flat electrodes.
  • FIGS. 1 to 6 A method for manufacturing a speaker diaphragm in an exemplary embodiment of the present invention is described with reference to FIGS. 1 to 6 .
  • a meshed cylindrical aluminum etching tunnel 2 is provided inside a cylindrical quartz reactive chamber 1 .
  • a speaker diaphragm 4 (corresponding to the speaker diaphragm 19 in the prior art) is held by a speaker diaphragm holder 3 in the reactive chamber 1 in parallel with other speaker diaphragms at approximately equal intervals.
  • a gas inlet 6 is provided on the reactive chamber 1 , and reactive gas A flows in from this gas inlet 6 through the etching tunnel 2 formed of meshed aluminum to the reactive chamber 1 .
  • Two pairs of electrodes 5 are provided facing each other on the outside face of the reactive chamber 1 .
  • a gas outlet 7 is also provided.
  • Ultra high polymer polyethylene resin called“LUMBER” (product name) manufactured by Mitsui Chemicals, Inc. is used for the speaker diaphragm 4 .
  • This“LUMBER” is formed into the speaker diaphragm 4 having a diameter of 16 cm by composite molding of injection or pressing, using an ultra high speed injection molding machine. The characteristics of this resin are shown in Table 1.
  • the size of the quartz reactive chamber 1 is 300 mm in diameter and 500 mm in length. As shown in FIG. 2, 30 speaker diaphragms 4 of diameter 16 cm are aligned at 15 mm intervals.
  • oxygen gas is employed for the reactive gas A.
  • FIG. 3 shows the changes in temperature during consecutive operations under the above conditions. As shown in FIG. 3, the temperature inside the reactive chamber is stabilized at about 45° C. even after consecutive operation for 12 hours, and no speaker diaphragm 4 was deformed.
  • the wettability of the speaker diaphragm 4 obtained through the above process is 50 dyn/cm or above on any part of the speaker diaphragm 4 . This allows the assumption that plasma is applied uniformly by the use of the meshed etching tunnel 2 .
  • FIG. 4 shows the durability of its wettability.
  • characteristic C in FIG. 4 The exemplary embodiment in which the primer is applied after plasma treatment is shown as characteristic C in FIG. 4 . It shows that the wettability immediately after treatment is a very high 50 dyn/cm, and the primer maintains a high wettability of 44 dyn/cm for considerable time, proving its stability.
  • the strength was compared between the speaker diaphragm 4 to which the primer was applied after plasma treatment in this exemplary embodiment and the voice coil 18 and edge 19 a were bonded using adhesives 12 and 13 ; and the conventional speaker diaphragm to which the primer was applied after corona discharge and the voice coil and edge were bonded.
  • the voice coil 18 shown in FIG. 5 has a diameter of 32 mm.
  • the adhesive 13 is a two-part reactive acrylic adhesive, and it is used for bonding the voice coil 18 onto the speaker diaphragm 4 .
  • the bonding strength was measured by pulling the voice coil 18 in the direction indicated by the arrow.
  • the edge 19 a shown in FIG. 6 is made of rubber, and it is bonded to the speaker diaphragm 4 using the adhesive 12 which is butyl rubber solvent adhesive.
  • the peeling strength was tested using a bonding area of 25 mm wide and 5 mm long.
  • the bonded area has peeled off in the conventional speaker using corona discharge by input of 70 W.
  • burning of the voice coil 18 occurred by input of 120 W.
  • no peeling of the bonded area has occurred, demonstrating extremely high bonding strength.
  • the reactive gas A approximately the same results as for oxygen were obtained by the use of nitrogen gas or air.
  • the material of the speaker diaphragm 4 approximately the same effect was obtained with polypropylene or nylon resin.
  • the exemplary embodiment provides electrodes 5 outside the reactive chamber 1 for plasma treatment. This enables the suppression of temperature rise in the reactive chamber 1 and prevents heat deformation of the speaker diaphragm 4 .
  • plasma can be uniformly applied by placing the speaker diaphragm 4 in a meshed metal frame, resulting in improved productivity.
  • the method for manufacturing a speaker diaphragm of the present invention disposes a resin speaker diaphragm made by injection molding or sheet forming by heating in the reactive chamber, and provides electrodes outside the reactive chamber. This enables the temperature inside the reactive chamber to be kept below the heat deformation temperature of the speaker diaphragm during surface activation of the speaker diaphragm by application of plasma. The temperature inside the reactive chamber is kept below the heat deformation temperature of the speaker diaphragm to prevent heat deformation of the speaker diaphragm and to suppress the occurrence of defects caused by heat deformation.
  • more than one speaker diaphragm is disposed inside the meshed metal frame in the reactive chamber at a predetermined interval to apply plasma almost uniformly.
  • the gas disperses almost uniformly inside the reactive chamber through the meshed metal frame so that the surface is almost uniformly activated, assuring high wettability and stable high quality of the speaker diaphragm.
  • the material used for the speaker diaphragm of the present invention is a monopolymer or copolymer of polyolefin resin such as polyethylene and polypropylene, or monopolymer or copolymer of polyamide resin. This enables a broad range of speaker diaphragms with improved bonding strength and stable quality to be manufactured.
  • a speaker manufactured using the speaker diaphragm manufactured as above thus has uniform and improved bonding strength between the speaker diaphragm and edge and/or voice coils, offering speakers with improved input power durability.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
US09/485,037 1998-06-12 1999-06-11 Method for manufacturing diaphragm for loudspeaker Expired - Fee Related US6627140B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US10/613,456 US20040094357A1 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same
US10/613,455 US7072485B2 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP10-164892 1998-06-12
JP10164892A JPH11355895A (ja) 1998-06-12 1998-06-12 スピーカ用振動板の製造方法
PCT/JP1999/003140 WO1999065272A1 (en) 1998-06-12 1999-06-11 Method of producing speaker diaphragm and speaker diaphragm formed by this method and speaker using this

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1999/003140 A-371-Of-International WO1999065272A1 (en) 1998-06-12 1999-06-11 Method of producing speaker diaphragm and speaker diaphragm formed by this method and speaker using this

Related Child Applications (2)

Application Number Title Priority Date Filing Date
US10/613,455 Division US7072485B2 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same
US10/613,456 Division US20040094357A1 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same

Publications (1)

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US6627140B1 true US6627140B1 (en) 2003-09-30

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Family Applications (3)

Application Number Title Priority Date Filing Date
US09/485,037 Expired - Fee Related US6627140B1 (en) 1998-06-12 1999-06-11 Method for manufacturing diaphragm for loudspeaker
US10/613,456 Abandoned US20040094357A1 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same
US10/613,455 Expired - Lifetime US7072485B2 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same

Family Applications After (2)

Application Number Title Priority Date Filing Date
US10/613,456 Abandoned US20040094357A1 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same
US10/613,455 Expired - Lifetime US7072485B2 (en) 1998-06-12 2003-07-03 Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same

Country Status (6)

Country Link
US (3) US6627140B1 (de)
EP (1) EP1005251B1 (de)
JP (1) JPH11355895A (de)
CN (1) CN1270582C (de)
DE (1) DE69939361D1 (de)
WO (1) WO1999065272A1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040094356A1 (en) * 1998-06-12 2004-05-20 Hitoshi Sato Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same
US20090262971A1 (en) * 2005-10-11 2009-10-22 Osamu Funahashi Speaker
US8889534B1 (en) * 2013-05-29 2014-11-18 Tokyo Electron Limited Solid state source introduction of dopants and additives for a plasma doping process

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3886391B2 (ja) * 2002-02-15 2007-02-28 シャープ株式会社 カード型装置、及び、それを備えた電子機器
TW201545564A (zh) * 2014-05-16 2015-12-01 B O B Co Ltd 喇叭振動片及其放電處理模製方法
USD835063S1 (en) * 2017-04-18 2018-12-04 Weiquan Wu Bluetooth loudspeaker

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6048696A (ja) * 1983-08-26 1985-03-16 Onkyo Corp スピ−カ用振動板の製造方法
JPH05168903A (ja) 1991-12-20 1993-07-02 Nisshin Flour Milling Co Ltd 粉体分散装置
JPH06225388A (ja) 1993-01-28 1994-08-12 Hokushin Ind Inc スピーカー

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5634297A (en) * 1979-08-29 1981-04-06 Kenzo Inoue Speaker unit
US4725345A (en) * 1985-04-22 1988-02-16 Kabushiki Kaisha Kenwood Method for forming a hard carbon thin film on article and applications thereof
JPH01279699A (ja) * 1988-05-06 1989-11-09 Mitsubishi Electric Corp スピーカ用振動板の製造方法
JPH0757039B2 (ja) * 1988-05-09 1995-06-14 株式会社ケンウッド 音響用振動板及びその製造法
JP3005099B2 (ja) * 1991-12-10 2000-01-31 フオスター電機株式会社 電気音響変換器
JP3194022B2 (ja) * 1992-07-06 2001-07-30 東京エレクトロン株式会社 プラズマ表面処理の制御装置
JPH06272035A (ja) * 1993-03-16 1994-09-27 Nippon Steel Corp プラズマ処理装置
JPH11355895A (ja) * 1998-06-12 1999-12-24 Matsushita Electric Ind Co Ltd スピーカ用振動板の製造方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6048696A (ja) * 1983-08-26 1985-03-16 Onkyo Corp スピ−カ用振動板の製造方法
JPH05168903A (ja) 1991-12-20 1993-07-02 Nisshin Flour Milling Co Ltd 粉体分散装置
JPH06225388A (ja) 1993-01-28 1994-08-12 Hokushin Ind Inc スピーカー

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
English translation of Form PCT/ISA/210(Aug. 24, 1999).
Japanese search report for PCT/JP99/03140 dated Aug. 24, 1999.

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040094356A1 (en) * 1998-06-12 2004-05-20 Hitoshi Sato Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same
US7072485B2 (en) * 1998-06-12 2006-07-04 Matsushita Electric Industrial Co., Ltd. Method for manufacturing diaphragm for loudspeaker, diaphragm for loudspeaker made thereby, and loudspeaker using the same
US20090262971A1 (en) * 2005-10-11 2009-10-22 Osamu Funahashi Speaker
US8009856B2 (en) 2005-10-11 2011-08-30 Panasonic Corporation Speaker
US8889534B1 (en) * 2013-05-29 2014-11-18 Tokyo Electron Limited Solid state source introduction of dopants and additives for a plasma doping process

Also Published As

Publication number Publication date
WO1999065272A1 (en) 1999-12-16
CN1270582C (zh) 2006-08-16
US20040094356A1 (en) 2004-05-20
US20040094357A1 (en) 2004-05-20
JPH11355895A (ja) 1999-12-24
CN1273015A (zh) 2000-11-08
EP1005251A4 (de) 2005-03-02
EP1005251B1 (de) 2008-08-20
US7072485B2 (en) 2006-07-04
EP1005251A1 (de) 2000-05-31
DE69939361D1 (de) 2008-10-02

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